Not applicable.
Not applicable.
1. Field of the Invention
This invention relates, generally, to a device for handling lumber.
2. Description of Related Art
In the manufacture of wooden I-beams, the rectangular wood flanges may be cut by rip saw from laminated billets. It is desirable to inspect the laminations at each cut prior to final assembly in order to assure the quality of the products to be made from the flanges. From the cutting process to positioning for final assembly, the flanges must be turned twice to facilitate the inspection process. By turning the flanges, each fresh cut is made visible. Because the flanges can be longer than 80 feet, turning the flanges manually is difficult and undesirable.
The simplest way of performing the first turn automatically is to use gravity in combination with a pair of conveyors. A conveyor apparatus is generally required as part of the manufacture and inspection process regardless of the technique used to turn the flanges. By adding a second conveyor and positioning it below the end of the first, a cascade is created. When the flanges reach the end of the first conveyor, they will follow the rounded end of the conveyor pulley and fall to the second conveyor having rotated approximately ninety degrees. Of course, the conveyance speed and the height difference of the conveyors must be set to suitable levels to achieve proper rotation. This simple cascade method works well when the flanges have an approximately square cross-section.
The previously described method is not sufficient when the aspect ratio of the flanges is significantly high. If the width-to-thickness ratio of the flanges is too great, the relatively narrow base upon which to flange must balance, coupled with the bounce of the flange upon impact, causes many of the flanges to fall onto their wide side. Generally the flanges fall forward due to their angular and linear momentum.
The second turn, which places the flanges into their final position for assembly, is another practical difficulty involved in the preparation and inspection process. Some of the flanges need to be returned to their original orientation while others need to be turned an additional ninety degrees.
Several mechanisms exist for reorienting objects of varying shape during a manufacturing process. However, there is no known device for simply and reliably rotating elongated members of varying aspect ratio about their longitudinal axis.
What is needed is a simple and inexpensive system for performing the turns. The first element of such a system is a device for turning flanges onto their narrow side which is more reliable than a simple cascade system. The second element returns the flanges to their original orientation or alternatively turns the flanges an additional ninety degrees.
It is an object of the present invention to provide a mechanism by which elongated members can be automatically rotated during a linear translation.
It is another object ofthe present invention to provide a mechanism capable of reliably performing the rotation on members of diverse cross-sectional aspect ratios.
It is another object of the present invention to provide a flange turning device which is relatively inexpensive.
These and other objects are achieved, according to the invention, by a device for rotating elongated objects of approximately rectangular cross-section about the longitudinal axis. The device includes a first turn section and a second turn section.
The first turn comprises two conveyor units arranged to allow a cascade effect as the members fall from the end of the first conveyor to the second conveyor. The members, positioned with their length generally perpendicular to the direction of conveyance, naturally rotate about their longitudinal axes as they fall. A dampening mechanism dissipates a portion of the energy of the members gained during the fall and places the members onto the second conveyor.
In one embodiment the dampening mechanism includes at least one rotating portion which catches the member in mid-fall and, through rotation, places the member on the second conveyor. The rotating portion of the mechanism is dampened to allow for smooth placement of the member onto the second conveyor. A spring returns the rotating portion back to its starting position after the flange member has been carried away.
The addition of a second rotating member to the dampening mechanism provides even further benefit. With a single rotating member, the member pushes up against the flange even after the flange has been placed on the second conveyor. This action is due to the spring return mechanism and can cause a significant force against the rear corner of the flange as the flange passes off of the rotating member. It can even cause the flange to fall forward onto its wide side. Disclosed herein is the use of a second rotating member which pushes the flange forward off of the first rotating member so that the first rotating member exerts no force on the flange once it has reached the second conveyor.
Also disclosed herein is a mechanism which accomplishes the desired task without the use of rotating members. In this embodiment, the dampening mechanism includes a horizontally positioned member translatable along its vertical axis and dampened by a piston-cylinder device. A second member powered by a fluidic connection with the first piston-cylinder device can be added to push the flange, imparting some forward momentum before the flange makes contact with the second conveyor.
The second turn comprises an upper and a lower section. Flanges to be turned back to their original orientation proceed to the upper section, while flanges to be turned an additional ninety degrees are directed to the lower section. The two sections operate on the same principle. The flanges are stopped on the second conveyor by stop pins to ensure the flanges enter the turner oriented perpendicular to the direction of conveyance. When the stop pins are removed the flanges approach the end of the second conveyor.
In the upper section a dog halts the top edge of each flange while an elastomeric wheel propels the bottom edge forward. The flange then drops away from the dog, falls on the wheel, and moves onto the discharge conveyor with the original surface facing up. In the lower section, a trip point halts the bottom edge of each flange while an elastomeric wheel propels the upper edge forward. The flange then falls onto the discharge conveyor with the desired orientation.